WO2020022118A1 - Recording device and recording method - Google Patents

Abstract

Provided is a recording device characterized by comprising: a recording means for ejecting a plurality of different pigment inks on a transfer body and forming an ink image; a processing means for performing a process so that each of the plurality of pigment inks applied to the transfer body forms a layer; and a transfer means for transferring the ink image from the transfer body onto a recording medium that is transported by a transporting means. The plurality of pigment inks include: four basic color pigment inks of the four basic colors of cyan, magenta, yellow, and black; and at least one pigment ink having a color other than the basic colors. A first ink, which is at least one ink among the basic color pigment inks, is applied to the transfer body later than a second ink among the inks having a color other than the basic colors, the second ink having a lower colorant concentration than the first ink.

Description

Recording device and recording method

The present invention relates to a recording device and a recording method.

多数 There have been many proposals for recording devices using ink jet technology. Among them, there are a direct drawing method in which ink is directly applied to a recording medium, and a transfer method in which ink applied to a transfer body is transferred to a recording medium. Patent Document 1 discloses a recording apparatus having an intermediate transfer body that carries an ink image, an ink ejection unit, and a transfer unit that transfers the ink image to a recording medium.

On the other hand, conventionally, in addition to the basic three primary colors necessary for printing, cyan (C), magenta (M), and yellow (Y), for higher image quality, so-called pale ink with similar colors but different densities, A recording apparatus provided with a special color having a different hue such as orange or green is disclosed.

Patent No. 5085893

(4) In a recording apparatus that sequentially applies ink on a transfer body and transfers the ink to a recording medium as described in Patent Document 1, the ink has a layered structure on the recording medium. In the case of such a layer structure, there is little mixing between different inks as seen in an apparatus using a direct drawing method of a dye, and a color is different from an image formed by a direct drawing method. In particular, in the case of an ink using a coloring material having a large particle size such as a pigment, how to form a layer structure is important for obtaining a desired coloring property. In particular, the basic colors CMY often have similar color material densities due to their balance. However, the ink used in addition to the basic colors to improve the saturation or the graininess of the image has the density and hue. Is significantly different from that of the base color ink. In order to sufficiently exhibit the effect of improving the image quality of the added ink, it is important to balance the basic color with the other inks added.

The present invention has been made in order to solve the above-mentioned problems, and has as its object to make each color of an image formed by laminating a plurality of ink layers better and more well-balanced.

Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals.

The accompanying drawings are included in the specification, constitute a part thereof, show embodiments of the present invention, and are used together with the description to explain the embodiments of the present invention.

Schematic diagram of the recording system Schematic diagram of recording head Block diagram of control system of recording system Explanatory diagram of an operation example of a recording system FIG. 4 is a diagram illustrating an image forming state and a light reflecting state. FIG. 4 is a diagram illustrating an image forming state and a light reflecting state. Diagram explaining the scattering intensity of two color materials FIG. 4 is a schematic diagram of a recording head according to a second embodiment. FIG. 9 is a schematic cross-sectional view illustrating an image forming state according to the second embodiment. FIG. 9 is a schematic cross-sectional view illustrating an image forming state according to the second embodiment. Schematic diagram of a recording head according to Embodiment 3. FIG. 4 is a schematic cross-sectional view illustrating an image forming state according to the first exemplary embodiment.

Hereinafter, preferred embodiments of the present invention will be described.

(Embodiment 1)
<Recording system>
FIG. 1 is a front view schematically showing a recording system 1 according to an embodiment of the present invention. The recording system 1 is a sheet-fed inkjet printer that manufactures a recorded material P ′ by transferring an ink image onto a recording medium P via a transfer body 2. The recording system 1 includes a recording device 1A and a transport device 1B. In the present embodiment, the X direction, the Y direction, and the Z direction indicate the width direction (full length direction), the depth direction, and the height direction of the recording system 1, respectively. The recording medium P is transported in the X direction.

<Recording device>
The recording apparatus 1A includes a recording unit 3, a transfer unit 4, peripheral units 5A to 5D, and a supply unit 6.

<Recording unit>
The recording unit 3 includes a plurality of recording heads 30 and a carriage 31. FIG. 2 is a view showing the configuration of the recording head, and is a view when the carriage 31 is viewed from the top of the apparatus in a direction toward the transfer 2. In the present embodiment, the recording unit includes eight recording heads. On the carriage, a head 30K that discharges black (K) ink (black ink), a head 30C that discharges cyan (C) ink, a head 30M that discharges magenta (M) ink, and a head that discharges yellow (Y) ink 30Y. Further, a head 30Lc for ejecting light cyan (Lc) ink having the same hue as cyan and lighter density, a head 30Lm for ejecting light magenta (Lm) ink having a lower density and the same hue as magenta, and a gray (lighter darker than black) (Gray) A head 30Gray for discharging ink is provided. This is a pigment ink having a pigment coloring material. Further, ink (for example, clear ink) containing no coloring material may be ejected. The clear ink can be used, for example, to improve the glossiness of an image. Alternatively, it can be used to reduce the glossiness of an image and give a matte feeling. In addition to the gloss control, an image transfer liquid for improving the transferability of an image from a transfer body to a recording medium can be used. The image transfer liquid is formed on the ink layer formed on the transfer body, and improves transferability by coming into contact with a recording medium. Therefore, the recording head for applying the image transfer liquid is disposed downstream of the recording head for applying various inks. In the present embodiment, a head 30S for discharging the image transfer liquid is provided. Each recording head is arranged on the carriage 31 and discharges ink onto the transfer body 2 which is a medium to be discharged, and forms an ink image of a recording image on the transfer body 2. As described above, according to the arrangement of the recording head shown in FIG. 2, the light cyan ink, the light magenta ink, and the gray ink are applied before any of the basic colors black ink, cyan ink, magenta ink, and yellow ink. Is done.

In the present embodiment, each recording head 30 is a full line head extending in the Y direction, and the nozzles are arranged in a range covering the width of the image recording area of the recording medium of the maximum usable size. . The recording head 30 has an ink ejection surface with nozzles opened on the lower surface thereof, and the ink ejection surface faces the surface of the transfer body 2 via a minute gap (for example, several mm). In the present embodiment, since the transfer body 2 is configured to move cyclically on a circular orbit, the plurality of recording heads 30 are radially arranged.

吐出 Each nozzle is provided with a discharge element. The ejection element is, for example, an element that generates pressure in the nozzle to eject ink in the nozzle, and a known inkjet head technology of an inkjet printer can be applied. As the ejection element, for example, an element that ejects ink by causing film boiling in ink by an electro-thermal converter to form bubbles, an element that ejects ink by an electro-mechanical converter, and an ink that utilizes static electricity to discharge ink. An element that discharges the ink may be used. From the viewpoint of high-speed and high-density recording, a discharge element using an electro-thermal converter can be used.

The carriage 31 supports the plurality of recording heads 30. Each recording head 30 has an end on the ink ejection surface side fixed to the carriage 31. Thereby, the gap between the ink ejection surface and the surface of the transfer body 2 can be maintained more precisely.

回復 A recovery unit (not shown) is provided at the rear of the recording system 1. The recovery unit 12 has a mechanism for recovering the ejection performance of the recording head 30. Examples of such a mechanism include a cap mechanism for capping the ink ejection surface of the recording head 30, a wiper mechanism for wiping the ink ejection surface, and a suction mechanism for suctioning the ink in the recording head 30 from the ink ejection surface under a negative pressure. be able to.

<Transfer unit>
The transfer unit 4 will be described with reference to FIG. The transfer unit 4 includes a transfer cylinder 41 and an impression cylinder 42. Each of these bodies is a rotating body that rotates around a rotation axis in the Y direction, and has a cylindrical outer peripheral surface. In FIG. 1, the arrows shown in the figures of the transfer cylinder 41 and the impression cylinder 42 indicate the rotation directions thereof, and the transfer cylinder 41 rotates clockwise and the impression cylinder 42 rotates counterclockwise.

The transfer cylinder 41 is a support that supports the transfer body 2 on its outer peripheral surface. The transfer body 2 is provided on the outer peripheral surface of the transfer cylinder 41 continuously or intermittently in the circumferential direction. When provided continuously, the transfer body 2 is formed in an endless belt shape. When provided intermittently, the transfer body 2 is formed into a plurality of segments in the form of a strip having ends, and the segments can be arranged on the outer peripheral surface of the transfer cylinder 41 at an equal pitch in an arc shape.

回 転 By the rotation of the transfer cylinder 41, the transfer body 2 moves cyclically on a circular orbit. The position of the transfer body 2 can be distinguished into the pre-ejection processing region R1, the ejection region R2, the post-ejection processing regions R3 and R4, the transfer region R5, and the post-transfer processing region R6 based on the rotation phase of the transfer cylinder 41. The transcript 2 passes through these regions cyclically.

The pre-ejection processing area R1 is an area where pre-processing is performed on the transfer body 2 before the recording unit 3 ejects ink, and is an area where processing is performed by the peripheral unit 5A. In the present embodiment, a reaction liquid is applied. The ejection region R2 is a formation region where the recording unit 3 ejects ink to the transfer body 2 to form an ink image. The recording unit 3 ejects ink to form an ink image while the image forming area of the transfer body 2 passes under the recording unit 3 once. The post-ejection processing areas R3 and R4 are processing areas for performing processing on the ink image after ink ejection, the post-ejection processing area R3 is an area where processing is performed by the peripheral unit 5B, and the post-ejection processing area R4 is a peripheral unit 5C. Is an area where the process is performed. The transfer area R5 is an area where the transfer unit 4 transfers the ink image on the transfer body 2 to the recording medium P. The post-transfer processing region R6 is a region where post-processing is performed on the transfer body 2 after the transfer, and is a region where processing by the peripheral unit 5D is performed.

The outer peripheral surface of the pressure drum 42 is pressed against the transfer body 2. At least one grip mechanism for holding the leading end of the recording medium P is provided on the outer peripheral surface of the impression cylinder 42. A plurality of grip mechanisms may be provided apart from each other in the circumferential direction of the impression cylinder 42. The ink image on the transfer body 2 is transferred when the recording medium P passes through a nip portion between the impression cylinder 42 and the transfer body 2 while being conveyed in close contact with the outer peripheral surface of the impression cylinder 42.

<Peripheral unit>
The peripheral units 5A to 5D are arranged around the transfer cylinder 41. In the case of the present embodiment, the peripheral units 5A to 5D are an applying unit, an absorbing unit, a heating unit, and a cleaning unit in this order.

The application unit 5A is a mechanism for applying a reaction liquid onto the transfer body 2 before the recording unit 3 discharges ink. The reaction liquid is a liquid containing a component that increases the viscosity of the ink. Here, increasing the viscosity of the ink means that the colorant or resin constituting the ink chemically reacts or physically adsorbs when it comes into contact with a component that increases the viscosity of the ink. That is, an increase in the viscosity of the ink is observed. In order to increase the viscosity of the ink, not only the case where the viscosity of the entire ink is increased, but also the case where the viscosity is locally increased due to aggregation of a part of the ink component such as a coloring material or a resin. Is also included.

機構 Examples of the reaction liquid application mechanism include a roller, a recording head, a die coating device (die coater), and a blade coating device (blade coater). If the reaction liquid is applied to the transfer member 2 before the ink is ejected to the transfer member 2, the ink that has reached the transfer member 2 can be immediately fixed. Thus, bleeding in which adjacent inks are mixed can be suppressed.

The absorption unit 5B is a mechanism for absorbing a liquid component from an ink image on the transfer body 2 before transfer. By reducing the liquid component of the ink image, bleeding of an image recorded on the recording medium P can be suppressed. If the reduction of the liquid component is described from a different viewpoint, it can be expressed that the ink constituting the ink image on the transfer body 2 is concentrated. Concentrating the ink means that a decrease in the liquid component contained in the ink causes an increase in the content ratio of the solid component such as a coloring material and a resin contained in the ink to the liquid component.

The absorption unit 5B includes, for example, a liquid absorbing member that comes into contact with the ink image and reduces the amount of the liquid component of the ink image. The liquid absorbing member may be formed on the outer peripheral surface of the roller, or the liquid absorbing member may be formed in an endless sheet shape and run cyclically. In terms of protecting the ink image, the liquid absorbing member may be moved in synchronization with the transfer member 2 by setting the moving speed of the liquid absorbing member to be the same as the peripheral speed of the transfer member 2.

The liquid absorbing member may include a porous body that comes into contact with the ink image. In order to suppress the adhesion of the ink solids to the liquid absorbing member, the pore diameter of the porous body on the surface in contact with the ink image may be 10 μm or less. Here, the pore diameter indicates an average diameter, and can be measured by a known means, for example, a mercury intrusion method, a nitrogen adsorption method, SEM image observation, or the like. The liquid component is not particularly limited as long as it does not have a fixed shape, has fluidity, and has a substantially fixed volume. For example, water, an organic solvent, and the like included in the ink and the reaction liquid are examples of the liquid component.

The heating unit 5C is a mechanism for heating the ink image on the transfer body 2 before the transfer. By heating the ink image, the resin in the ink image melts, and the transferability to the recording medium P is improved. The heating temperature can be equal to or higher than the minimum film forming temperature (MFT) of the resin. The MFT can be measured by a generally known method, for example, each device based on JIS @ K # 6828-2: 2003 or ISO2115: 1996. From the viewpoint of transferability and image fastness, heating may be performed at a temperature higher than MFT by 10 ° C. or more, and further, may be performed at a temperature higher by 20 ° C. or more. As the heating unit 5C, for example, a known heating device such as various lamps such as infrared rays, a hot air fan and the like can be used. In terms of heating efficiency, an infrared heater can be used.

(4) The cleaning unit 5D is a mechanism for cleaning the transfer body 2 after the transfer. The cleaning unit 5D removes ink remaining on the transfer member 2, dust on the transfer member 2, and the like. As the cleaning unit 5D, a known method such as a method of bringing a porous member into contact with the transfer member 2, a method of rubbing the surface of the transfer member 2 with a brush, and a method of scraping the surface of the transfer member 2 with a blade is used as appropriate. Can be. The cleaning member used for cleaning may have a known shape such as a roller shape or a web shape.

As described above, in the present embodiment, the application unit 5A, the absorption unit 5B, the heating unit 5C, and the cleaning unit 5D are provided as peripheral units, but a cooling function of the transfer body 2 is provided to some of these units, or , A cooling unit may be added. In the present embodiment, the temperature of the transfer body 2 may increase due to the heat of the heating unit 5C. If the ink image exceeds the boiling point of water, which is the main solvent of the ink, after the recording unit 3 discharges the ink onto the transfer member 2, the absorption performance of the liquid component by the absorption unit 5B may be reduced. By cooling the transfer body 2 so that the ejected ink is maintained at a temperature lower than the boiling point of water, the absorption performance of the liquid component can be maintained.

The cooling unit may be a blowing mechanism that blows air to the transfer body 2 or a mechanism that brings a member (for example, a roller) into contact with the transfer body 2 and cools this member by air cooling or water cooling. Further, a mechanism for cooling the cleaning member of the cleaning unit 5D may be used. The cooling timing may be a period after the transfer and before the application of the reaction liquid.

<Supply unit>
The supply unit 6 is a mechanism that supplies ink to each recording head 30 of the recording unit 3. The supply unit 6 may be provided on the rear side of the recording system 1. The supply unit 6 includes a storage unit TK for storing ink for each type of ink. The storage unit TK may be configured by a main tank and a sub tank. Each storage section TK and each recording head 30 communicate with each other through a flow path 6a, and ink is supplied from the storage section TK to the recording head 30. The flow path 6a may be a flow path for circulating ink between the storage unit TK and the recording head 30, and the supply unit 6 may include a pump or the like for circulating ink. A degassing mechanism for degassing bubbles in the ink may be provided in the middle of the flow path 6a or in the storage part TK. A valve for adjusting the ink pressure and the atmospheric pressure may be provided in the middle of the flow path 6a or in the storage section TK. The height of the reservoir TK and the recording head 30 in the Z direction may be designed so that the ink liquid level in the reservoir TK is lower than the ink ejection surface of the recording head 30.

<Transport device>
The transport device 1B is a device that feeds the recording medium P to the transfer unit 4 and discharges the recorded material P ′ on which the ink image has been transferred from the transfer unit 4. The transport device 1B includes a feed unit 7, a plurality of transport cylinders 8, 8a, two sprockets 8b, a chain 8c, and a recovery unit 8d. In FIG. 1, an arrow inside the figure of each component of the transport device 1B indicates the rotation direction of the component, and an arrow outside indicates the transport path of the recording medium P or the recorded material P ′. The recording medium P is transported from the feeding unit 7 to the transfer unit 4, and the recorded matter P 'is transported from the transfer unit 4 to the collection unit 8d. The feed unit 7 may be referred to as an upstream side in the transport direction, and the collection unit 8d may be referred to as a downstream side.

The feeding unit 7 includes a stacking unit on which a plurality of recording media P are stacked, and includes a feeding mechanism for feeding the recording media P one by one from the stacking unit to the transport drum 8 at the uppermost stream. Each of the transfer cylinders 8 and 8a is a rotating body that rotates around a rotation axis in the Y direction, and has a cylindrical outer peripheral surface. At least one grip mechanism for holding the leading end of the recording medium P (or the recorded matter P ') is provided on the outer peripheral surface of each of the transport cylinders 8 and 8a. The gripping operation and the releasing operation of each gripping mechanism are controlled so that the recording medium P is transferred between adjacent transport cylinders.

<Control unit>
Next, a control unit of the recording system 1 will be described. 3 and 4 are block diagrams of the control unit 13 of the recording system 1. The control unit 13 is communicably connected to a host device (DFE) HC2, and the host device HC2 is communicably connected to a host device HC1.

(4) The host device HC1 generates or stores document data that is the basis of a recorded image. The document data here is generated in the form of an electronic file such as a document file or an image file. This document data is transmitted to the host device HC2, and the host device HC2 converts the received document data into a data format usable by the control unit 13 (for example, RGB data expressing an image in RGB). The converted data is transmitted as image data from the host device HC2 to the control unit 13, and the control unit 13 starts a recording operation based on the received image data.

In the present embodiment, the control unit 13 is roughly divided into a main controller 13A and an engine controller 13B. The main controller 13A includes a processing unit 131, a storage unit 132, an operation unit 133, an image processing unit 134, a communication I / F (interface) 135, a buffer 136, and a communication I / F 137.

The processing unit 131 is a processor such as a CPU, executes a program stored in the storage unit 132, and controls the entire main controller 13A. The storage unit 132 is a storage device such as a RAM, a ROM, a hard disk, and an SSD, stores programs executed by the CPU 131 and data, and provides a work area to the CPU 131. The operation unit 133 is, for example, an input device such as a touch panel, a keyboard, and a mouse, and receives an instruction from a user.

The image processing unit 134 is, for example, an electronic circuit having an image processor. The buffer 136 is, for example, a RAM, a hard disk, or an SSD. The communication I / F 135 communicates with the host device HC2, and the communication I / F 137 communicates with the engine controller 13B. In FIG. 4, the broken arrows indicate the flow of processing of image data. Image data received from the host device HC2 via the communication IF 135 is accumulated in the buffer 136. The image processing unit 134 reads the image data from the buffer 136, performs predetermined image processing on the read image data, and stores the read image data in the buffer 136 again. The image data after the image processing stored in the buffer 136 is transmitted from the communication I / F 137 to the engine controller 13B as print data used by the print engine. The engine controller 13B controls the driving of the recording system 1 and performs an image forming operation.

<Operation example>
FIG. 4 is a diagram schematically showing an example of the recording operation. While the transfer cylinder 41 and the impression cylinder 42 are being rotated, the following steps are cyclically performed. First, the reaction liquid L is applied from the application unit 5A onto the transfer body 2 (state ST1). The portion of the transfer body 2 to which the reaction liquid L has been applied moves as the transfer cylinder 41 rotates. When the site to which the reaction liquid L has been applied reaches below the recording head 30, ink is ejected from the recording head 30 to the transfer body 2 (state ST2). Thus, an ink image IM is formed. At that time, the ejected ink mixes with the reaction liquid L on the transfer body 2, thereby promoting the aggregation of the coloring material. The ejected ink is supplied to the recording head 30 from the storage section TK of the supply unit 6.

イ ン ク The ink image IM on the transfer member 2 moves with the rotation of the transfer member 2. When the ink image IM reaches the absorption unit 5B, a liquid component is absorbed from the ink image IM by the absorption unit 5B (state ST3). When the ink image IM reaches the heating unit 5C, the heating unit 5C heats the ink image IM, the resin in the ink image IM melts, and the ink image IM is formed (state ST4). The recording medium P is transported by the transport device 1B in synchronization with the formation of such an ink image IM.

The ink image IM and the recording medium P reach the nip portion between the transfer body 2 and the impression cylinder 42, the ink image IM is transferred to the recording medium P, and a recorded matter P 'is manufactured (state ST5). After passing through the nip portion, the image recorded on the recorded matter P 'is photographed by the inspection unit 9A, and the recorded image is inspected. The recorded material P 'is transported by the transport device 1B to the collection unit 8d.

(4) When the ink image IM on the transfer body 2 has reached the cleaning unit 5D, the portion where the ink image IM is formed is cleaned by the cleaning unit 5D (state ST6). After the cleaning, the transfer body 2 has made one rotation, and the transfer of the ink image onto the recording medium P is repeatedly performed in the same procedure. In the above description, for ease of understanding, the transfer of the ink image IM to one recording medium P is performed once in one rotation of the transfer body 2. The transfer of the ink image IM to the plurality of recording media P can be continuously performed.

<Ink>
Here, the ink applied to the present embodiment will be described.

(Color material)
A pigment is used as a coloring material contained in the ink applied to the present embodiment. The type of pigment that can be used as a coloring material is not particularly limited. Specific examples of the pigment include inorganic pigments such as carbon black; and organic pigments such as azo, phthalocyanine, quinacridone, isoindolinone, imidazolone, diketopyrrolopyrrole, and dioxazine. One or more of these pigments can be used as needed.

The content of the pigment in the ink is preferably 0.5% by mass to 15.0% by mass, more preferably 1.0% by mass to 10.0% by mass, based on the total mass of the ink. .

(Dispersant)
As the dispersant for dispersing the pigment, a known dispersant used for ink-jet inks can be used. In particular, in the embodiment of the present invention, it is preferable to use a water-soluble dispersant having both a hydrophilic part and a hydrophobic part in the structure. In particular, a pigment dispersant made of a resin copolymerized with at least a hydrophilic monomer and a hydrophobic monomer is preferably used. Each monomer used here is not particularly limited, and known monomers are preferably used. Specifically, examples of the hydrophobic monomer include styrene and other styrene derivatives, alkyl (meth) acrylate, benzyl (meth) acrylate, and the like. Examples of the hydrophilic monomer include acrylic acid, methacrylic acid, and maleic acid.

酸 The acid value of the dispersant is preferably from 50 mgKOH / g to 550 mgKOH / g. The weight average molecular weight of the dispersant is preferably 1,000 or more and 50,000 or less. The mass ratio between the pigment and the dispersant (pigment: dispersant) is preferably in the range of 1: 0.1 to 1: 3.

In the present embodiment, it is also preferable to use a so-called self-dispersion pigment, which does not use a dispersant but is capable of dispersing by modifying the surface of the pigment itself.

(Resin fine particles)
The ink applied to the present embodiment can be used by incorporating various fine particles having no coloring material. Among them, resin fine particles are preferable because they may be effective in improving image quality and fixability.

材質 The material of the resin fine particles that can be used in the present embodiment is not particularly limited, and a known resin can be appropriately used. Specific examples include polyolefin, polystyrene, polyurethane, polyester, polyether, polyurea, polyamide, polyvinyl alcohol, poly (meth) acrylic acid and salts thereof. Further, a homopolymer such as polyalkyl (meth) acrylate and polydiene, or a copolymer obtained by polymerizing a plurality of monomers for producing these homopolymers may be used. The weight average molecular weight (Mw) of the resin is preferably from 1,000 to 2,000,000. The amount of the resin fine particles in the ink is preferably from 1% by mass to 50% by mass, more preferably from 2% by mass to 40% by mass, based on the total mass of the ink.

In the aspect of the present embodiment, the resin fine particles are preferably used as a resin fine particle dispersion in a liquid. The method of dispersion is not particularly limited, but a so-called self-dispersion type resin fine particle dispersion obtained by dispersing a monomer having a dissociative group using a resin obtained by homopolymerization or copolymerization of a plurality of kinds of monomers is preferable. Here, examples of the dissociative group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of the monomer having the dissociable group include acrylic acid and methacrylic acid. A so-called emulsified dispersion type resin fine particle dispersion in which resin fine particles are dispersed by an emulsifier can also be suitably used in the present embodiment. As the emulsifier referred to here, a known surfactant is preferable irrespective of low molecular weight or high molecular weight. The surfactant is preferably a nonionic surfactant or a surfactant having the same charge as the resin fine particles.

樹脂 The resin fine particle dispersion used in the aspect of the present embodiment preferably has a dispersed particle size of 10 nm or more and 1000 nm or less, and more preferably has a dispersed particle size of 100 nm or more and 500 nm or less.

In addition, when preparing the resin fine particle dispersion used in the aspect of the present embodiment, it is also preferable to add various additives for stabilization. Examples of the additive include n-hexadecane, dodecyl methacrylate, stearyl methacrylate, chlorobenzene, dodecyl mercaptan, a blue dye (bluing agent), and polymethyl methacrylate.

(Surfactant)
The ink that can be used in the present embodiment may include a surfactant. Specific examples of the surfactant include acetylene glycol ethylene oxide adduct (acetylenol E100, manufactured by Kawaken Fine Chemical Co., Ltd.). The amount of the surfactant in the ink is preferably 0.01% by mass or more and 5.0% by mass or less based on the total mass of the ink.

(Water and water-soluble organic solvents)
The ink used in the present embodiment can contain water and / or a water-soluble organic solvent as a solvent. The water is preferably water deionized by ion exchange or the like. Further, the content of water in the ink is preferably 30% by mass or more and 97% by mass or less based on the total mass of the ink.

The type of the water-soluble organic solvent used is not particularly limited, and any known organic solvent can be used. Specific examples include glycerin, diethylene glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, and thiodiglycol. Further, hexylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, ethanol, methanol and the like can be mentioned. Of course, two or more kinds selected from these can be mixed and used.

(4) The content of the water-soluble organic solvent in the ink is preferably 3% by mass or more and 70% by mass or less based on the total mass of the ink.

(Other additives)
Inks that can be used in the present embodiment may be, if necessary, other than the above components, such as a pH adjuster, a rust inhibitor, a preservative, a fungicide, an antioxidant, an antioxidant, a water-soluble resin, and neutralization thereof. It may contain various additives such as an agent and a viscosity modifier.

<Reaction liquid>
The reaction liquid contains a component for increasing the viscosity of the ink (ink viscosity increasing component). The increase in viscosity of the ink means that a colorant or a resin, which is a part of the composition constituting the ink, chemically reacts or physically adsorbs by contact with the ink viscosity increasing component, This includes cases where an increase in the viscosity of the entire ink is recognized. In addition, it also includes a case where viscosity of the ink locally increases due to aggregation of a part of a component such as a coloring material constituting the ink. This ink viscosity increasing component has the effect of reducing the fluidity of a part of the ink and / or the ink composition on the medium to be discharged, thereby suppressing bleeding and beading during image formation with the ink. Known components such as polyvalent metal ions, organic acids, cationic polymers, and porous fine particles can be used as the ink viscosity increasing component. Among them, polyvalent metal ions and organic acids are particularly preferable. It is also preferable to include a plurality of types of ink viscosity increasing components. Incidentally, the content of the ink thickening component in the reaction liquid is preferably 5% by mass or more based on the total mass of the reaction liquid.

Examples of polyvalent metal ions include divalent metal ions such as Ca2 +, Cu2 +, Ni2 +, Mg2 +, Sr2 +, Ba2 +, and Zn2 +, and trivalent metal ions such as Fe3 +, Cr3 +, Y3 +, and Al3 +.

Examples of the organic acid include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, glutaric acid, and glutamic acid. . Further, fumaric acid, citric acid, tartaric acid, lactic acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, oxysuccinic acid, dioxysuccinic acid, and the like. Can be

The reaction solution can contain an appropriate amount of water or a low-volatile organic solvent. The water used in this case is preferably water deionized by ion exchange or the like. The organic solvent that can be used for the reaction solution applied to the present invention is not particularly limited, and a known organic solvent can be used.

The reaction solution can be used by appropriately adjusting the surface tension and viscosity by adding a surfactant and a viscosity modifier. The material used is not particularly limited as long as it can coexist with the ink viscosity increasing component. Specific examples of the surfactant used include an acetylene glycol ethylene oxide adduct and a perfluoroalkyl ethylene oxide adduct.

In the recording system described above, a color material layer containing a color material is formed on the paper by sequentially applying ink to the transfer body coated with the reaction liquid and transferring the ink to the paper.

(4) Even in an apparatus in which a recording medium is used as a medium to be ejected and ink ejected from a recording head is applied directly to the recording medium without passing through a transfer body, it is possible to sequentially apply ink one by one to form a coloring layer. The ink is mainly composed of a coloring material and a solvent. A small amount of the solvent in the ink applied to the recording medium remains in the coloring layer due to volatilization or penetration into the recording medium. The coloring layer is mainly composed of a coloring material. The coloring material adheres to the ink absorbing layer in the ink receiving layer formed on the recording medium, or stays in a space or the like of the recording medium to form a coloring layer. The coloring layer is formed mainly inside the recording medium, although it differs depending on the ink and the recording medium. When the amount of the coloring material for forming the coloring layer is small, the amount of the coloring material adsorbed on the adsorbing layer and the amount of the coloring material remaining in the space of the medium is reduced, and the thickness of the coloring layer is reduced. Therefore, in such a system, when the same amount of ink having different color material concentrations is applied, a color developing layer having a thickness corresponding to the color material is formed. For this reason, even if the color material concentration in the ink is small or large, it is difficult for a large difference in the color material density in the formed color forming layer to occur.

On the other hand, in the printing apparatus according to the present embodiment, first, ink is sequentially applied onto the transfer body to which the reaction liquid has been applied in the pretreatment step. When the ink comes into contact with the reaction liquid, it aggregates. Therefore, when ink is ejected one color at a time, an ink aggregation layer is formed each time, and the ink does not mix with each other. Layering is thus promoted. Further, the liquid component is reduced in the absorption step, and the ink aggregate layer in which the resin fine particles are melted in the heating step is transferred to the recording medium, so that the ink does not penetrate much into the recording medium, and most of the ink remains on the recording medium. And promote layering. Further, since the ink contains resin fine particles in addition to the color material, the color-forming layer is formed of a mixture of the color material and the resin fine particles. Even if the same amount of ink having different coloring material concentrations is applied, a large difference in the thickness of the coloring layer is unlikely to occur due to the presence of the resin fine particles. That is, the color material layer formed of the ink having the low color material density has a smaller color material density in the color material layer than the color layer formed of the ink having the high color material density. As described above, in the recording apparatus of the present embodiment, if there is a difference in the color material density in the ink, a difference is likely to occur in the color material density in the color forming layer. Significant effect on color balance.

FIG. 5A is a diagram illustrating an image formation state and reflected light of an image recorded using the A ink and the B ink. The A ink and the B ink each form a color forming layer and overlap on the paper surface, and the figure is a schematic diagram showing a cross section. The A ink includes the color material A and exhibits the A color. The B ink includes a color material B and exhibits a B color. In this image, since the color-forming layers of the A ink and the B ink overlap, the color mixture of A + B is exhibited. The structure of the color-forming layer is such that the lowermost layer is paper, the intermediate layer is a B-color layer formed of B ink, and the uppermost layer is an A-color layer formed of A ink.

に 対 し To the incident light, the total of the light reflected by each layer or interface is observed as reflected light. Here, for the sake of simplicity, only reflected light in one direction is shown, but there are actually specularly reflected light components and diffused light components, which are reflected in various directions. There are the following five types of reflected light. First, there is reflected light 501 reflected on the surface of the A-color layer, which is the surface of the image forming layer. Since there is no absorption by the coloring material, the light becomes white as the incident light. Reference numeral 502 denotes light reflected by the color material in the A color layer, which is selectively absorbed / reflected for each wavelength according to the A color material, and the color of the reflected light is A color. Reference numeral 503 denotes light reflected on the surface of the B color layer, which is the interface between the A color layer and the B color layer, and is light of the A color because it is not affected by the B color material. Reference numeral 504 denotes light reflected inside the B color layer, which is selectively absorbed / reflected for each wavelength according to the B color material. In addition to the reflected light exhibiting the B color, incident light and outgoing light are reflected. Since the light passes through the A color layer, the light emitted from the surface is a mixed color of A color and B color. Reference numeral 505 denotes reflected light that is reflected at the interface between the B color layer and the paper surface, and is a mixed color of the A color and the B color similarly to 504.

FIG. 5B is a diagram illustrating the reflection inside the coloring layer in more detail. The color forming layer is composed of a pigment coloring material contained in the ink and resin fine particles. The resin fine particles are heated in the image forming step to form a substantially uniform layer, in which a coloring material is present. The incident light is repeatedly reflected and scattered by the color material, and becomes reflected light of a color unique to the color material by wavelength-selective absorption by the color material. For example, the light 506 is light that is reflected by a coloring material and is observed as reflected light. Reference numeral 507 denotes light observed as reflected light through a scattering process by a coloring material inside the ink layer. Further, reference numeral 508 denotes light incident on the lower layer while being scattered by the coloring material. Reference numeral 509 denotes light that reaches the lower layer without being scattered by the coloring material. Through such various reflection / scattering steps, part of the incident light reaches the lower layer, and part of the light is observed as reflected light.

The reflected light R observed in an image composed of two layers of the A color layer and the B color layer is represented by the following equation.
R = R _A + T _A · R _B · T _A + T _A · T _B · R _g · T _B · T _A where
R _A: reflectance of the A color layer _T A: transmittance of A color layer _R B: reflectance of B color layer _T B: transmittance of B color layer _{R g:} reflectance of the paper

As can be seen from the above equation, the color development of B color is always T _A , that is, the transmittance of the A color layer. That is, unless the transmittance of the A color layer is increased, the B color does not develop well.

小 さ い Small coloring materials such as dyes do not have a significant scattering effect. However, the effect of the scattering component is large in the pigment coloring material. In a color material layer having a large scattering component, the transmittance decreases. That is, if the scattering component of the upper layer is large, the transmittance is reduced, and the color of the lower layer is not satisfactorily colored, which has the effect of lowering the coloring efficiency and disturbing the color balance. Here, in order to develop the color of the lower layer, the ink of the color of the lower layer may be increased, but the amount of ink that can be held as an ink film on the transfer body is limited. Also, there is a method of exclusively providing dots so that two color forming layers do not overlap as much as possible, but this method is suitable for low-density image formation, and forms an image of half tone or higher, particularly high density. Has overlap between different colors.

By the way, the lower the concentration of the coloring material, the smaller the scattering. FIG. 6 is a diagram illustrating the scattering intensity of two cyan inks having different color material densities. The horizontal axis is the light wavelength (nm), and the vertical axis is the scattering intensity. The first ink having a high color material density is indicated by a solid line, and the second ink having a low color material density is indicated by a dotted line. From the figure, it can be seen that the degree of scattering of the first ink is greater than that of the second ink.

From the above, the color-forming layer formed with the ink having a low color material concentration has a lower scattering intensity and a higher transmittance of the color-forming layer than the color forming layer formed with the high-ink.

In the present embodiment, of the color material layers formed in layers, the color layer formed by ink having a low color material concentration is used as the upper layer, the transmittance of the upper layer is high, and the color of the lower color layer is easily obtained. As a result, the color forming efficiency of the lower color forming layer is increased, and the color balance at the time of color mixing is improved. Here, the color material concentration is a comparison by weight%.

The color materials used in the present embodiment include light C, light M, and Gray (light K) in addition to the basic colors CMY and K. Light C, light M, and light K are collectively referred to as "light color". Light color inks are often provided to reduce graininess and lower the color material density so that the dots are less noticeable than the base color. Specifically, the color material concentration of CMYK is 1 to 10% by weight, whereas the light color ink has a color material amount of about 1/2 to 1/10 of the basic color of the same color system.

で は The light color ink has a lower colorant density between the basic color ink and the light color ink. Therefore, scattering inside the formed color forming layer is small and the transmittance is high. In other words, when the light-colored ink and the basic color ink are layered, the color-forming layer formed of the light-colored ink is formed in the upper layer, and the color-forming layer formed of the basic color ink formed in the lower layer is also formed with good color, and the color balance of the mixed colors is improved. Is improved, so that a good image can be obtained.

In the present embodiment, as described above, first, a reaction liquid is applied to a transfer body, ink is applied thereon, a layer is formed on the transfer body, and then the layer is transferred to paper. Therefore, in order to form an upper layer on the paper surface, a group of light color inks (light C, light M, and Gray (light K)) is applied to the transfer body before the basic color ink groups (CMY and K). In this way, the lower layer 102 on the recording medium 103 shown in FIG. 10 is formed of one of the basic color ink groups (CMY and K) or a plurality of ink layers. For example, when forming an image of cyan hue, light C forms the upper layer 101 and C forms the lower layer 102. For example, when forming a blue hue, the light C and light M ink layers form the upper layer 101, and the C and M ink layers form the lower layer 102. In this case, light C and light M layers are formed in the upper layer in the order of application. The same applies to the lower layer 102.

(Embodiment 2)
In the first embodiment, an example has been described in which an ink having a low color material density of a similar color with respect to the basic color is provided. In the present embodiment, an example is shown in which a color material ink having a hue different from the basic color is provided.

記録 In this embodiment, the recording system is the same as in the first embodiment. However, different types of ink are provided. In this embodiment, a special color ink having a hue different from the basic color is provided in place of the light color ink for the purpose of further expanding the color reproduction range. Specifically, there are orange (О), green (G), and blue (B), which are hues between the basic colors CMY. Thereby, the color gamut in the saturation direction of the color of the recorded image can be expanded. FIG. 7 is a schematic diagram of a recording head applied in the present embodiment, and is a view of the recording head as viewed from above the apparatus as in FIG. As in the first embodiment, the recording head includes eight recording heads. In addition to the heads 30S, 30K, 30C, and 30Y that eject the image transfer liquid and the basic colors CMY and K, respectively, a head 30 (O) that ejects orange ink, a head 30G that ejects green ink, and a head that ejects blue ink 30B. In this case, the orange ink, the green ink, and the blue ink are ejected to the transfer body after the basic color. Regardless of the hue of the image to be formed, the special color ink is ejected to the transfer body later than the basic color ink used for color reproduction.

イ ン ク The ink added to extend the color reproduction range is not limited to these. Red (R) or violet (V) of another hue may be used. Further, the number of inks to be added may be selected from one color to plural colors according to the apparatus. In addition, a plurality of inks of different colors may be provided in adjacent hues. For example, even with the same “green” hue, the hue and the achievable lightness / saturation are different depending on the color material, and the color reproduction range is different. A plurality of different inks having such close hues may be provided. Further, two kinds of dark and light inks may be provided, each of which is a special color hue intended to widen the same color reproduction range such as blue (B) and light blue (LB).

も Regardless of the combination, for the basic color and the special color of the other hue, the ink having a low color material density is formed in the upper layer. FIG. 8 is a schematic sectional view of an image formed by overlapping C and G. 8A shows a recording medium 83 in which a layer 81 of green ink is formed as an upper layer and a layer 82 of cyan ink is formed as a lower layer. FIG. 8B shows a layer 82 formed of cyan ink as an upper layer and a layer 81 made of green ink as a lower layer. Have been. 8A and 8B, the G ink amount and the C ink amount are the same. In this embodiment, the color material density of the C ink is 4% by weight, and the color material density of the G ink is 3%. When the color-forming layer made of the G ink having a low color material concentration is formed in the upper layer, the scattering intensity of the upper layer is lower, the transmittance is higher, and the lower layer C ink also develops a good color. 8A and FIG. 8B, the color balance is better when the layer 81 made of green ink is the upper layer and the layer 82 made of cyan ink is the lower layer shown in FIG. 8A than in the reverse state shown in FIG. 8B. And good images can be obtained.

も Also in this embodiment, first, a reaction liquid is applied to a transfer body, ink is applied thereon, and a layer is formed on the transfer body, and then the layer is transferred to a recording medium. Therefore, in order to form an upper layer on the recording medium, a special color ink other than the basic color may be applied to the transfer body before the basic color ink.

(Embodiment 3)
In the case of an ink jet recording apparatus, a part of the ink ejected from the upstream head may not reach the recording surface and may float as a small droplet ink mist. For example, there is a possibility that an air current generated by the movement of the medium to be ejected (the transfer cylinder in the case of the first embodiment) in the traveling direction may cause the mist to move forward, and the ink mist may adhere to the downstream head. Can be Therefore, it is considered that, when the ink heads of similar colors are arranged close to each other, even if mist adheres, the ink head is inconspicuous and a good image can be recorded in many cases.

In the present embodiment, the recording system is the same as that of the first embodiment, and the inks provided are light C, light M, and gray light inks in addition to the basic colors CMY and K. FIG. 9 is a configuration diagram of a recording head applicable in the present embodiment, and is a schematic diagram similar to FIG. As in the first and second embodiments, the recording head includes eight recording heads. A head 30Gray for ejecting Gray ink, a head 30K for ejecting K ink, a head 30Lc for ejecting light C ink, a head 30C for ejecting C ink, a head 30Lm for ejecting light M ink, a head 30M for ejecting M ink, A head 30Y for discharging Y ink and 30S for discharging image transfer liquid are provided. With this configuration, ink heads of similar colors are arranged close to each other. For example, the heads 30Lc and 30C have an adjacent relationship, and the head 30Lm and the head 30M have an adjacent relationship. This makes it possible to form a layer of ink of similar color and low color material density on the upper layer side and a layer of ink with high color material density on the lower layer side.

Also, similar bright colors are often used together, for example, a bright cyan color close to white is mainly composed of light cyan and cyan. Such a plurality of inks often used at the same time has an effect of raising the color-forming layer formed by the ink having a low color material concentration. It is described in Embodiment 1 that the color forming layer formed by the ink having the low color material density has a lower scattering intensity due to the color material, a higher transmittance of the color forming layer, and a good color of the lower color forming layer. As you did.

(Other embodiments)
The present invention can be applied to a recording apparatus that is not a transfer system. A recording apparatus may be used in which a line head is used to form layers while drying or curing one color at a time in the order of ink application to form a color material layer on paper. In the case of such a recording apparatus, a basic color serving as a lower layer is first provided on the paper surface to form a color forming layer, and a light color is provided thereon to form a light color forming layer. In any case, the same effects as those of the above-described first to third embodiments can be obtained by forming the color-forming layer formed of ink having a low color material concentration as the upper layer.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to make the scope of the present invention public.

This application claims the priority of Japanese Patent Application No. 2018-139504 filed on Jul. 25, 2018, the entire contents of which are incorporated herein by reference.

Claims (11)

A transfer body that passes through an ink image forming area and a transfer area,
Recording means for ejecting a plurality of different pigment inks to the transfer body in the formation area, and forming an ink image on the transfer body,
Performing a process for promoting layering of each of the applied plurality of pigment inks so that each of the plurality of applied pigment inks is formed on the transfer body by being discharged by the recording unit. Processing means;
Conveying means for conveying the recording medium;
Transfer means for transferring the ink image from the transfer body to a recording medium conveyed by the conveyance means,
A recording device comprising:
The plurality of pigment inks include at least a pigment ink of a basic color of cyan ink, magenta ink, yellow ink, and black ink, and at least one pigment ink different from the basic color. Wherein the first ink, which is at least one of the inks, is applied to the transfer body later than the second ink having a lower colorant density than the first ink among the inks different from the basic color. . The at least one pigment ink different from the basic color is an ink of the same color as the cyan ink, and a light cyan ink having a lower colorant concentration than the cyan ink, and an ink of the same color as the magenta ink, and 2. The recording apparatus according to claim 1, further comprising a light magenta ink having a color material density lower than that of the magenta ink. 2. The recording apparatus according to claim 1, wherein the at least one or more pigment inks different from the basic color include a plurality of inks having hues different from the basic color. 3. 4. The recording apparatus according to claim 3, wherein the plurality of inks having a hue different from the basic color include a blue ink and a green ink. 5. The recording apparatus according to claim 3, wherein the plurality of inks having a hue different from the basic color include orange ink. 6. The transfer medium according to claim 1, wherein the pigment ink of the basic color is applied to the transfer body after any of the pigment inks different from the at least one of the basic colors. The recording device according to claim 1. 7. The recording device according to claim 1, wherein the recording unit ejects ink to the transfer body in one pass of the formation area of the transfer body to form an ink image on the transfer body. 8. Item 2. The recording device according to item 1. 8. The method according to claim 1, wherein the processing unit is an applying unit that applies a liquid for aggregating the pigment on the transfer body before the plurality of pigment inks are applied by the recording unit. The recording device according to claim 1. 8. The recording apparatus according to claim 1, wherein the processing unit is a liquid absorbing unit configured to absorb a liquid in the ink image from the ink image. 9. Recording means for ejecting a plurality of pigment inks on a recording medium to form an ink image on the recording medium, and each time one ink is applied on the recording medium by being ejected by the recording means; Processing means for performing processing for promoting layering of each of the plurality of pigment inks applied, so that the pigment ink forms a layer,
A recording device comprising:
The plurality of pigment inks include at least a pigment ink of a basic color of cyan ink, magenta ink, yellow ink, and black ink, and at least one pigment ink different from the basic color. Wherein the first ink, which is at least one of the inks, is applied to the recording medium before the second ink having a lower colorant density than the first ink among the inks different from the basic color. apparatus. A step of ejecting a plurality of different pigment inks in the formation area to the transfer body passing through the ink image formation area and the transfer area to form an ink image on the transfer body; and A processing step for accelerating the layering of each of the plurality of pigment inks provided so that each of the plurality of pigment inks forms a layer; and A transfer step of transferring an image, and a recording method comprising:
The plurality of pigment inks include at least a pigment ink of a basic color of cyan ink, magenta ink, yellow ink, and black ink, and at least one pigment ink different from the basic color. Wherein the first ink, which is at least one of the inks, is applied to the transfer body later than the second ink having a lower colorant density than the first ink among the inks different from the basic color. .

Images